Best Personal Formula

Discussion in 'Prius c Fuel Economy' started by jack1953, Jun 8, 2015.

  1. jack1953

    jack1953 New Member

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    After owning my Prius for 2 months, I've figured out the best formula for getting the best gas mileage.

    Keep in mind, I am a musician, and travel frequently in a 50 mile semi-radius to the north, south, and east, since I live on the west coast of Florida, I do not have to travel west.

    If my speed is under 45mph, I continuously use the pulse method. If I am in a 35, 30, or 25mph zone, I can drive exclusively on EV power, 90-95% of the time.
    If my speed is over 45mph, and on flat lands (I'm in SW Florida where it's flat everywhere except for bridges and overpasses), I use Cruise Control every chance I get.

    I've been able to average between high 50s and low 60s mpg.
    I also avoid freeway driving when I can, but when I do use the freeway, I cruise at 60mph.
    Obviously I give myself plenty of travel time calculation.
     
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  2. bisco

    bisco cookie crumbler

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    well done!(y)
     
  3. StealthFighter

    StealthFighter Junior Member

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    Good observations, jack1953. I also want to add a few of mine.

    I travel about 70+ miles daily, 35+ miles one way & I noticed after a couple of months of driving my 2015 prius c that my mpgs are different each way. I average about 64mpg (with a record of 67) going to work (if I concentrate on driving economically), but going home I only get 48-54mpgs. When I drive "normally" (like I drive my 2013 VW passat), my mpgs go down to 45-48 going to work, 40-43 going home. Here are my observations so far.

    1. The biggest factor in mpgs is the terrain, I believe. Slow, downhill routes give the best mpgs. So planning your route is always helpful.
    2. The next factor is the weight. When I got new rims, I added weight & my mpgs went down. Passengers/cargo affect mpgs by as much as 5-10% per 100 lbs (by my best guesstimate).
    3. Concentrating on driving economically is the key.

    I think that your guide above sums it up. The prius c is really designed for city driving, so high speeds should be avoided if maximizing fuel economy is your goal. But then again, even if I drive normally & relax a little bit, I still get better mpgs than my other cars.
     
  4. ufourya

    ufourya We the People

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    There is nothing major wrong with your ideas. However, I am confused by your statement that you can drive exclusively on EV power 90-95 % of the time in 25 - 35 mph zones.

    I have tried my damnedest to spend as much 'time' in EV as possible during my stunt driving runs. The best I can do is around 85% of the 'time'. I put time in quotes because the car can measure percentage of distance traveled in EV, but not 'time', and this is during runs where the car is getting well over 100 MPG. (See my avatar which indicates 78% EV). If you can instruct me how to achieve 90 -95 %, I'd really appreciate it.
     
  5. ufourya

    ufourya We the People

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    Went out this morning, Jack, and made a little run to see where I could max out EV%. Now, anyone could start on top of a mountain and coast down to post a really high %. So I imposed a a couple of rules on myself: Begin and end at the same place or the same elevation and go at least 20 miles (arbitrary and small, but reasonable enough to get a ball park figure.) Plus, I drove in a 35 mph zone without exceeding the limit.

    Fuel cost set in computer is $2.50.


    IMG_3854 (800x600).jpg IMG_3856 (800x597).jpg

    This was the best I could do today. I figure between 116 and 119 MPG. (The $.50 could be just a hair from turning to $.51) EV 84% is the max I have a photo of, although I remember being @ 85% once.
     
  6. spyderx

    spyderx Member

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    Your tire PSI also affects MPG a lot...
    I set mine down to 40/39 front/rear from mid 40's out of dealer's lot and she took a 3 to 5 MPG hit...

    Also, the faster the ICE heats up the higher the MPG climbs... a lot!
    And, on the return from work trips seem to net +5% higher MPG then going to work due to warmer ICE.

    I average about 53 MPG calculated.
     
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  7. EconoModder

    EconoModder Junior Member

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    Yes, keep those tire pressures up, stick with stock size tires. I currently run 47f, 44r. I bought some 195/55/15's also and run both sizes on 2 sets of Konig Helium rims which are about 4.5lbs lighter than stock. The mileage is definitely better on the stock size tires though than the 195's. Handling is superior on the 195's of course, but the lack of a rear sway bar gives the car an unsatisfying feeling in the corners, even with the increased grip.

    You can really only spend extended time in EV if you're on a slight downhill. You can get some pretty awesome numbers if your trip leads you slightly downhill and you end your trip on a delpeted battery. I got 73.9mpg on a 10 mile trip last week that was mostly flat. Prob a 100ft starting elevation ending at sea level.
     
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  8. ufourya

    ufourya We the People

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    You can spend extended time (that is, a large percentage of the distance traveled) even when beginning and ending at the same point in a trip - or the same elevation. Yes, tires, psi, and terrain etc., have an effect, but attention to what you are doing, and when you are doing it, has the major influence.

    Take a peek around.

    This thread contains both assertions that one can drive in EV exclusively 90 to 95 % of the time on flat terrain and that one can 'really only' achieve 'extended' time in EV on a 'slight' decline. Both assertions are in the main, mistaken. The evidence is all around you.
     
  9. EconoModder

    EconoModder Junior Member

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    ^^^Teach me oh great one!

    Now, I know pulsing and gliding you can do it...Question is how hard do you accelerate on the "pulse" because you can get higher percentage of time in EV if you floor it on the pulse, then glide for longer periods of time. But is that more efficient than slowly getting back up to speed after each glide?
     
  10. ufourya

    ufourya We the People

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    :) I'm still waiting for Jack to teach us how he does the 90-95% thing. I can't find any flat ground around here, so I'm willing to be corrected; but I don't think it is possible to maintain that percentage over a significant distance and end up at the same start/stop elevation.

    The way to determine how long or hard to pulse is tied intimately with the terrain. Here is a suggestion to help determine a method for your specific route. (I realize traffic may be a great hindrance, but you gotta do what you can.) This method will temporarily screw up the actual fuel cost as calculated by the car's computer, but sacrifices must be made.

    First, in the settings screen, set the fuel cost to $9.99. This is as high as it will go. Then, breaking your route into individual pulses and glides, carefully note how much it 'costs' on the ECO savings screen for each method you employ for each pulse and subsequent glide. You will answer your own questions about how long and how hard. The more you 'spend', the less effective the method. There is great secret, Grasshopper - no easy answers, only work and patience.

    ADDENDUM: I will say that any time you 'floor it' the traction battery springs to life, and this will, sooner or later, require replenishment at the expense of running ICE. You do not want to have ICE come on while you are in a nice, long glide or while you are stopped at a light. On the other end of the spectrum, an overly timid pulse is not as efficient as one that gets you to speed in a timely fashion. Yes, that is rather vague, which is why I recommend the procedure above for learning the best method for each particular terrain. If you can P&G and keep the battery from draining to two bars, you are on the right track.
     
    #10 ufourya, Jun 17, 2015
    Last edited: Jun 21, 2015
  11. StealthFighter

    StealthFighter Junior Member

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    I saw a slight improvement in my MPGs when I adjusted the tire pressure. Thanks for the tip, guys!

    I also found this interesting blog. I think I'll try out some of these techniques on Monday...
    Mike with a Prius: Prius-ing for Dummies - beginner Prius mileage tips
     
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  12. ufourya

    ufourya We the People

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    For those more visually oriented, this video covers much of the same material for newbies as the fine link you provided.
     
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  13. StealthFighter

    StealthFighter Junior Member

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    Here's another one on the prius c. His hilly, back road route's similar to my daily commute to work. I can only muster 67.8 mpg, need to work on my technique to break 70.

     
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